Lightning arrester



I N V EN TOR.

G. R. FOLDS.

LIGHTNING ARRESTER.

FILED NOV. 12, 1919.

E WK Dec. 19, 1922.

ATTORNEYS.

Patented Dec. 19, 19 22.

uylrao STATES PATENT-OFFICE.

GEORGE R. FOLDS, O]? EVANSTON, ILLINOIS, ASSIGNOB TO COOK ELECTRICCOMPANY,

OF CHICAGO, ILLINOIS, A CORPORATION OF. ILLINOIS.

LIGHTNING ARRESTER.

Application filed November 12,1919. Serial 110. $3 7,510.

T 0 all whom it may concern.

Be it known that I, Gnono'n R. Forms, a

citizen of the United States, residin at the interior of a pole'caEvanston, in the county of Cook and tate of Illinois, have invented newand useful Im rovements in Lightning Arresters, of which the followingis a full, clear, concise, and exact description, reference being had tothe accompanying drawing, forming a part of this specification.

This invention relates to lightning arresters, and more particularly toimproved means for electrically separating the line and ground springsof lightning arresters used on low voltage electric circuits, such astelephone, telegraph and signal systems to provide for high potentialdischarges.

Lightning arresters used for high potential discharges on low voltageelectric circuits are equipped with means whereby a discharge gap isprovided to consummate the high potential discharges.

The construction herein comprises two conducting plates, preferablyconstructed of either carbon or copper, and separated by a suitabledielectric, the high potential jumping from one plate to the other.

One object of my invention is to provide an improved form of saw toothtype arrester, in which a serrated or toothed edge is separated from asuitable ground plate by the desired air space to insure the dischargeof a determined minimum potential.

Another object of this invention consists in the production of animproved and efiicient form of separating means for a saw tooth arresterconstruction, which means may be readily assembled and which consists ofparts which, when assembled, clampingly engage each other to constitutean integral unit whereby when the separating means is removed from thearrester, it is removed as a single piece. This obviates the handling ofa plurality of parts when the separating means are inserted and removedfrom arresters, and thus avoids much inconvenience due to the droppingand losing of the individual parts used' in constructing said separatingmeans.

Other objects of the invention will become apparent from the followingdescription, the accompanying illustrations and the ap pended claims.

For the purposes of illustration and description, the specificembodiment of this invention is shown in the accompanying drawingsandinwhich-v i "Fig. 1 illustrates a perspective view of b e terminalequipped with the .lmproved arrester separating means;

Fig. 2- illustrates in perspective the respective parts of the saw tootharrester separatin means shown in Fig. 1 disassociated rom one anotherbut ositioned in the respective order in which t ey are combined whenplaced--in position in the light- IllIl arrester; and

ig. 3 illustrates a view in perspective of the assembled saw tootharrester separating means.

The improved form of arrester separating means herein illustrated anddescribed can obviously be used with substantially any and all kinds ofcommercial lightning arrester constructions, and is shown and describedherein in connection with a pole cable terminal for illustrativepurposes only. The pole cable terminal illustrated is well known tothose skilled in the art, and a very brief description thereof willconsequently be sufficient. This pole cable terminal box 10 is providedwith a cover 11 and side panels 12 extend vertically from the base 13 ofthe cable terminal box, said panels being sesured to the base and upperportion of the terminal box by means of angle members 14. Suitablymounted on the vertical side panels 12 are spring clips 15 and 16 whichreceive fuses 17 which are held in said clips with a permanent tension.

The line wires 18 enter the base portion of the cable terminal box andare fanned out and electrically connected to the spring clips 15 asshown at 19. The cable wires 20 also enter the cable terminal boxthrough the base portion thereof, said cable wires 20 being likewisefanned out and electrically connected to the inner s. ring clips 16. Inthe ordinary operating 0 the apparatus, the line current will flow fromthe line wires' 18 through the spring clips 15, the fuse member 17,through the spring clip 16 and out to the cable wires 20. To prevent anydamage to the cable wires 20, a lightning arrester 21 is located betweenthe spring clip lish a by-pass for high potentials whereby such highpotentials will not reach the cable but will be shunted through thearrester to ground, thus preventing the burning-outs in the cable.

The lightning arrester comprises the spring clip 16, the ground panel 12and the improved separating means hereinafter to be described in detail.The separating means is fitted with a plate 22 having a serrated or sawtoothed edge, but obviously this plate could be constructed in any otherdesired form or shape. The plate 22 has integrally formed... inwardlyextending flanges 23 and 2.4:,the flange 23 having a serrated 01' sawtoothed edge as illustrated at 25. This plate is made of conductingmaterial, preferably sheet brass, and is equipped with the upsetportions 26 which are adapted to properly guide and position the platein the arrester spring clip 16.

Positioned between the flanges 23 and 24 of the plate 22 is a dielectric27 which is composed of some suitable non-conducting material,preferably celluloid or mica. This dielectric fits into and conforms tothe contour of the flanged plate 22, whereby the non-conducting materialextends to the saw toothed edge of this plate and extends beyond theopposite flange portion 24.

A carbon block 28 is positioned next to the grounded verticallyextending side panel 12 and is in electrical contact therewith. Thiscarbon block is fitted with a central slot 29 whereby said block may beused either next adjacent the side panel ground plate 12 or inconnection with the spring clip 16 in which case the slot serves toproperly position and securely hold the block 28. As shown in Figs. 2and 3, the carbon block is cut away on the opposite side from said slot29 so as to form shoulder portions 30 whereby the block may be insertedbetween the flange portions 23 and 24 of the plate member 22, whicharrangement with the dielectric held therebetween form an integral unit.

As shown in Fig. 3, the saw tooth separating means is so formed that theparts may be assembled as an integral unit before being inserted betweenthe side panel ground plate 12 and the spring clip 16 of the lightningarrester. In assembling the parts of the separating means, thedielectric 27 is first placed inside of the plate 22 with its inwardlyextending flanges resting against the flanges 23 and 24 of saidconducting plate. The plate 22 with the enclosed dielectrio is thenslipped over the cut away portions 30 of the carbon block 28, said platewith the enclosed dielectric snugly fitting over this portion of theblock 28. It will be evident, therefore, that the carbon block 28,conducting plate 22 and dielectric 27 may be assembled before beinginserted between the side panel ground plate 12 and the spring clipmember 16 in which condition it is preferably carried in stock and inthe tool kits of the repair man and the troubleshooter. The advantagesof this construction, therefore, reside in the fact that there islittle, if any, danger of the parts becoming separated and of the partsof the arrester being lost or mislaid, as frequently happens to mica orcelluloid due to its transparency when separated from the other elementsof the separating means.

When the various elements, namely, the conducting plate 22, dielectric27 and carbon block 28 are all assembled in position, asillustrated inFigs. 1 and 3, it will be evident that the carbon block is in directcontact with the ground member and that the plate is in directdielectrical" contact with the spring clip 16.

However, there is no electrical contact between the carbon block 28 andthe plate 22 since they are insulated from each other by the dielectric27. The toothed edge of the plate is separated from the shoulder 30 ofthe carbon block 28 by the thickness of the dielectric, the parts beingso manufactured that when the dielectric is placed between the plateand'the carbon block, this desired distance between the toothed edge ofthe plate 22 and the carbon block 28 is maintained in order to providefor the discharge of the minimum potential at which the arrester isdesigned to operate. The dielectric consequently may be the meansutilized to give the desired separation between the saw toothed edge ofthe plate electrically connected to the spring clip 16 and the shoulderportion of the carbon block connected to the ground member 12.

From the preceding description, it will be evident that when the variouselements shown in Fig. 2 are assembled in their cooperative positions,the line wire 18 is connected to the conducting plate 22, and the sidepanel ground member 12 is in contact with the carbon block 28, thecarbon block being separated from the plate by means of the dielectric27. The high potential will consequently be discharged through thetoothed edge 25 to the carbon block 28.

Further, when for the purposes of inspection, replacement or repair itbecomes necessary to remove the separating means, the said separatingmeans will be removed as an integral unit, thereby avoiding the handlingof a plurality of parts and the separation of the plate, dielectric orcarbon block.

If replacement is desired, the inspector can obviously take an assembledseparating unit from his kit and insert it in place without wasting anytime in handling the small parts of which it is built.

This invention is not limited to the specific embodiments hereinillustrated and described, but it is capable of many variations andmodifications which come within the spirit and scope of the invention.as set forth in the following claims.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

' 1. In a lightning arrester in combination, line and ground members, anassembled integral unit electrically separating said members includingconducting members separated by a dielectric, said conducting membersbeing mechanically connected to each other through a dove-tail joint thetenon and mortise of which. are electrically separated by saiddielectric, and means forming an electric discharge path between saidconducting members.

2. In a device of the character described in combination, an assembledintegral unit comprising a metallic plate having a flange portion, theedge of sa1d flange portion being serrated, a conducting block, and adielectric between said metallic plate and conducting block, saidconducting block, metallic plate and dielectric snugly engaging eachother to form said assembled integral unit.

3. In acdevice of the character described in combination, an assembledintegral unit comprising a metallic plate having flanges thereon, adielectric conforming to said plate and flan es and received betweensaid flanges, a con ucting block received between the flange portions ofsaid dielectric, said metallic plate, dielectric and conducting blocksnugly en aging each other so as to form said assembled integral unit.

4. A lightning arrester comprising a metallic plate in the form of amortise having a serrated longitudinal edge, a conducting block providedwith a tenon to engage said mortised metallic plate and with a lateralflange portion, a dielectric interposed between said plate and saidconducting block, and means for properly locating the assembled membersin operative position, said serrated edge being spaced from said lateralflange ortion which it subtends.

5. A lightning arrester comprising a conducting member in the form of amortise, a second conducting member in the form of a tenon to engagesaid mortise thereby forming a dove-tail joint connection between saidconductin members, one of said conducting members being provided with alongitudinally extending serrated edge that is spaced from the other ofsaid conducting members, and a dielectric for electrically separatingsaid conducting members from each other.

6. A lightning arrester comprising two conducting members one of whichis provided with a serrated edge, said members being mechanicallyconnected to each other through a dove-tail joint, and means forelectrically insulating said members from each other, said serrated edgeserving as an electric discharge path from one of said members to theother from which it is spaced to form a spark-gap.

7 A lightning arrester comprising a conducting member in the form of amortise, a second conducting member in the form of a tenon to engagesaid mortise thereby forming a dove-tail joint connection, one of saidmembers being provided with a longitudinally extending serrated edgethat is spaced from the other of said members, a dielectric forelectrically separating said members from each other, and means forproperly loeating the assembled members 1n operative position.

In witness whereof, I have hereunto subscribed my name.

GEORGE R. FOLDS.

Witnesses:

J. 0. Boom, B. C. Mnnm.

